The present invention is related to aircraft fire suppression systems, and more specifically a system and method of fire suppression utilizing inert gases.
Currently, some lavatory and galley venting (LGV) systems exhaust air from lavatories, galleys, and optional crew rests to provide ventilation and airplane level smoke management. The exhaust air provides suction to aspirate the cabin and flight deck zone temperature sensors, crest rest zone temperature sensors, and bulk cargo zone temperature sensors. The exhaust air also provides supplemental or backup heat sink capability to remove waste heat from the power electronics cooling system. The exhaust air is subsequently vented overboard. The forward and aft cargo areas and bulk container heating system provides ventilation and heating to the aft cargo and bulk container compartments (AC/BC). The air used for this heating system is typically vented to the lower bilge/keel beam area of an aircraft and subsequently also vented overboard. These systems are thermodynamically inefficient, as work is done to ingest, compress, and condition the LGV and AC/BC air streams, and the excess is vented overboard and not utilized.
Current fuel tank inerting systems require an external air intake, where an air separation module is supplied with ram air or conditioned compressor bleed air in order to produce nitrogen-enriched air for fuel tank inerting. The air separation module is part of a nitrogen generation system, which provides nitrogen-enriched air for fire suppression. However, the ram air inlet causes an increase in aerodynamic skin friction due to the size of the ram air intake opening. Compressor bleed air is an undesirable parasitic loss. Additionally, some systems may require additional nitrogen tanks or bottles for effective fire protection and suppression. To date all cargo bay fire suppression systems use halon-1301, which is an ozone depleting substance. The Montreal Protocol mandated the phase out of halon-1301 for commercial and industrial fire protection. However, no viable options currently exist for commercial fire protection of cargo bays.